TEHRAN, Iran - Iran's foreign minister said Tuesday he hoped his sudden resignation would reinforce the position of his fellow diplomats, hinting that a dispute with the security apparatus and hard-liners led to a "deadly poison for foreign policy."

Mohammed Javad Zarif's move sent shockwaves through Iran, where tensions are already running high over America's withdraw from the nuclear deal he helped negotiate with President Hassan Rouhani.

The Tehran stock market dropped 1,927 points Tuesday, down some 1.16 per cent. The Iranian rial, which has rapidly depreciated amid uncertainty over the deal's future, stood around 135,600 rials to $1. It had been 32,000 to the dollar at the time of the deal.

The state-run IRNA news agency said Zarif told colleagues his resignation would aid in "restoring the ministry to its legal position in foreign relations."

Zarif elaborated in an interview published Tuesday by the daily Jomhuori Eslami.

"A deadly poison for foreign policy is that it becomes the subject of factionalism and parties' quarrel," Zarif reportedly said. "There should be trust toward servants of foreign policy on the national level. Without trust in them, everything will go with the wind."

The remark appeared to be aimed at other bodies within Iran's government. Zarif was not present for a meeting with Syrian President Bashar Assad on Monday. Assad was warmly received by Supreme Leader Ayatollah Ali Khamenei as well as Gen. Qassem Soleimani, the commander of an elite unit of the Revolutionary Guard.

Zarif's resignation called to mind a similar move in 1988 by then-Prime Minister Mirhossein Mousavi, said to have been triggered by outside pressure. Supreme Leader Ayatollah Ruhollah Khomeini at the time opposed the resignation and Mousavi continued his job.

It was unclear if Assad's visit to Tehran had an impact on Zarif's decision. On Tuesday, authorities shuttered the pro-reform Ghanoon daily which had in its early edition of the day called Assad an "uninvited guest" on the front page. The paper said on its Telegram channel that it was closed until further notice.

Later on Tuesday, and without mentioning the resignation, Rouhani praised Zarif as well as Oil Minister Bijan Zanganeh and Central Bank chief Abdolnasser Hemmati as soldiers on the battlefield against U.S. pressure.

"Today, the front line against the U.S. are the foreign and oil ministries as well as the Central Bank," Rouhani said in a televised address. "Zarif, Hemmati and Zanganeh have stood in the front line."

Prominent pro-reform lawmaker Ali Motahari said Zarif's resignation came in response to the "interventions by unaccountable bodies in foreign affairs."

He said Rouhani was unlikely to accept the resignation "since there is no alternative" for Zarif.

However, not everyone was sad to see Zarif go. Lawmaker Behrouz Nemati said that hard-line lawmaker Javad Karimi Ghodousi brought him cookies to celebrate Zarif leaving.

Iran's powerful parliamentary committee on national security and foreign affairs was scheduled to discuss Zarif's resignation later Tuesday though its pronouncements are considered mostly advisory.

Analysts say Rouhani faces growing political pressure from hard-liners within the government as the nuclear deal unravels. Iranian presidents typically see their popularity erode during their second four-year term, but analysts say Rouhani is particularly vulnerable because of the economic crisis assailing the rial, which has hurt ordinary Iranians and emboldened critics to openly call for his ouster.

The son of a wealthy family, Zarif overcame hard-line objections and Western suspicions to strike the accord with world powers that saw Iran limit its uranium enrichment in exchange for the lifting of crippling economic sanctions.

But the deal was later challenged by the administration of President Donald Trump, which pulled America out of the accord. In doing so, Trump also fueled Iranian suspicions about U.S. intentions dating back to the 1979 Islamic Revolution. Zarif had faced withering criticism at home after he shook hands with President Barack Obama.

"Zarif is gone, good riddance. As long as I am here Iran will not get nuclear weapons," he wrote in Hebrew on Twitter. Iran has always said its nuclear program is for peaceful purposes, and U.N. inspectors say it is still complying with the 2015 nuclear accord.

U.S. Secretary of State Mike Pompeo, commenting on Zarif's resignation, said "we'll see if it sticks."

"Our policy is unchanged — the regime must behave like a normal country and respect its people," he said.